47 



Descriptions of Seven New Species of the Genus 10. 



BY ISAAC LEA. 



Read December 24th, 1861, 



When I proposed in 1831* to form the new genus Io for Mr. Say's Fusus 

 fluviatilis, there were no other allied species known to naturalists. I then pro- 

 posed also to change the specific name to fusiformis, as being more appropriate, 

 and I gave a figure under this name. At that time the canons of nomenclature 

 were not so well understood nor so strict as they hare since been ; and it is 

 only justice to Mr. Say to relinquish my specific name, and to replace his. Sub- 

 sequently in 1834, I proposed a new species under the name of Io spinosa, 

 (Trans. Am. Phil. Soc, vol. v. pi. 19, fig. 79.) More recently Mr. Anthony, in 

 the Proceedings of the Academy, (I860,) proposed four new species ; three of 

 which I think belong to the two previously established species. Mr. Lovell 

 Reeve, in his beautiful : - Conchologia Iconica," has recently issued among his 

 monographs one of tho genus Io with numerous plates and full descriptions. 

 In this he has introduced a number of species, most of which I think more ap- 

 propriately belong to Prof. Haldeman's genus Lilhasia — the species of which 

 form a very excellent group, which he separated from Melaiiia and Anculosa — 

 but which Mr. Reeve does not seem to recognise. Of the true Io I also think 

 he has considered several varieties as species. 



Io nodosa. — Testa tuberculata, elevato-conica, virido-cornea, vittata ; spira 

 regulariter conica ; suturis valde impressis ; anfractibus instar denis, planula- 

 tis, medio tuberculatis, infia striatis; apertura parviuscula, rhomboidea, intus 

 vittata; labro acuto etsigmoideo ; columella alba et valde contorta ; canali bre- 

 viuscula. 



Hab. — Tennessee River, Alabama? f Wm. Spillman, M. D. 



Io eobdsta. — Testa canaliculate, paulisper tuberculata, elevato-conicS, pal- 

 lido-cornea, infra obsolete vittata; spira regulariter conica; suturis valde im- 

 pressis ; anfractibus instar denis, apud apicem planulatis, infra canaliculata ; 

 apertura parviuscula, rhomboidea, intus vittata ; labro acuto et sigmoideo ; co- 

 lumella pallido-salmonii; canali breviuscula. 



jjal. — Tennessee River, Alabama? Wm. Spillman, M. D. 



* Trans. Amer. Phil. Soc, January, 1831. 



t Dr. Spillman simply gave Tennessee River as the habitat of these species, but did 

 not mention what part. They are probably from Alabama. 



